共查询到20条相似文献，搜索用时 15 毫秒
1.
U. Fuchs K. Zimmermann H. W. Sauer K.‐H. Trautmann G. Biallas 《Materialwissenschaft und Werkstofftechnik》2008,39(8):531-544
Similar and dissimilar friction stir welded joints made from AA2124+25 % SiC and AA2024 An aluminium matrix composite (AMC) consisting of an AA2124 matrix reinforced by 25 vol.% SiC particles was used to produce similar AMC+AMC and dissimilar AMC+2024‐T3 joints by friction stir welding. When the particle reinforced composite was located on the retreating side, material mixing was less intense for dissimilar joints. Nevertheless, a higher strength has been determined for this arrangement due to a hook‐like interlocking of both materials. Tensile test and S‐N fatigue behaviour is shown to be compromised by alignment of the reinforcement particles perpendicular to loading direction already in the particle reinforced base material. Welding residual stresses were determined through the cut‐compliance method in terms of stress intensities acting at the crack tip. The underlying residual stress distribution in the un‐cracked structure was calculated by the weight function method. Longitudinal tensile residual stresses were found to be higher in the monolithic material as compared to the particle reinforced composite. This held true both for similar and within dissimilar joints. Growth behaviour of cracks crossing the joint line was described and correlated with residual stresses for similar joints. 相似文献
2.
E. Hegelmann P. Hengst P. Hollmann J. Thronicke A. Buchwalder R. Zenker 《Materialwissenschaft und Werkstofftechnik》2019,50(11):1428-1439
The present work aims to improve the wear resistance of the austenitic stainless steel X6CrNiMoTi17‐12‐2. In view of the potential use of this alloy, however, corrosion resistance should be maintained where possible. An electron beam surface treatment (cladding) was performed, and the cobalt‐based alloy Stellite® 12 was used as the wear‐resistant material. The presented results show the effects of several electron beam oscillation figures during the cladding process with regard to layer bonding, microstructure formation and hardness. The surface hardness achieved was 576±18 HV 0.3, almost three times higher than that of the base material (203±3 HV 0.3). The scratch energy density – which represents the resistance to abrasive wear – could be increased by a factor of 1.5. Under abrasive‐adhesive stress loading conditions, the determined wear volume decreased by a factor of almost 5. Based on the corrosion investigations carried out, it was possible to prove that in comparison to the base material, the tendency towards pitting corrosion could be almost completely suppressed. 相似文献
3.
High frequency welding of low alloyed sheet steel with integrated thermo‐mechanical treatment Described are the seam characteristics of high frequency welded low‐alloyed sheet steel blanks. The focus of the investigations is directed to static and fatigue strength. In addition, a possibility to perform a thermo‐mechanical treatment of the welding seam will be presented. Also the effect of the thermo‐mechanical treatment on the cold formability of the welding seam is analysed. 相似文献
4.
Using self‐made electromagnetic centrifugal casting machine, optical microscopy (OM) and D/max2200pc X‐ray diffraction, the solidification microstructure and phases of as‐cast high speed steel(HSS) roll made by sand casting, centrifugal casting and electromagnetic centrifugal casting were investigated. The experiment results show that the phases of as‐cast high speed steel (HSS) roll are alloy carbide (such as W2C, VC, Cr7C3), martensite and austenite. The centrifugal casting and electromagnetic centrifugal casting can apparently improve the solidification structure of HSS roll. With the increase of electromagnetic field intensity (B), the volume fraction of austenite in the HSS solidification structure increased obviously and eutectic ledeburite decreased, the secondary carbide precipitated from the austenite is more fine and distribution of secondary carbide is more even. 相似文献
5.
A. Horn M. Panzenböck H. Clemens G. Posch 《Materialwissenschaft und Werkstofftechnik》2013,44(11):889-896
High strength low alloy steels are used in many different engineering areas. A commonly used joining technique for those steels is fusion welding. Generally, these components have to withstand fatigue due to dynamic loading. Using thermal joining techniques affect the mechanical properties of the steel. This study focuses on the influence of the heat input on the microstructure of high strength low alloy steels (S690). Furthermore, the fatigue behaviour with special regard to crack initiation and crack propagation is characterized. 相似文献
6.
In this paper, we design and prepare five kinds of high‐boron high‐speed steel roll materials. The microstructure, mechanical property and wear resistance of high‐boron high‐speed steel roll materials were studied by means of optical microscopy (OM), scanning electron microscopy (SEM), X‐ray diffraction (XRD) and hardness measurement, impact test and abrasion test. The results show that as‐cast microstructure of high‐boron high‐speed steel consists of martensite, retained austenite and borocarbide. Hardness of as‐cast high‐boron high‐speed steel excels 64 HRC. In unmodified high‐boron high‐speed steel, eutectic borocarbide is distributed in a network along the grain boundary. With the addition of RE‐Mg‐Ti compound modifier, the networks of borocarbide is broken. The hardness of high‐boron high‐speed steel gradually decreased with the increase of tempering temperature. Under the same conditions, the impact toughness of unmodified high‐boron high‐speed steel roll material is slightly lower than that of modified steel. The wear resistance of modified high‐boron high‐speed steel roll material is greater than that of high‐carbon high‐vanadium high‐speed steel roll. 相似文献
7.
C. Meran Asst. Prof. Dr. V. Kovan A. Alptekin 《Materialwissenschaft und Werkstofftechnik》2007,38(10):829-835
The objective of this work is to demonstrate the feasibility of friction stir welding (FSW) AISI 304 austenitic stainless steels. The tool used was formed of a tungsten‐based alloy. The specimens were welded on an 11 kW vertical milling machine. Defect‐free welds were produced on 2.5 mm plates of hot‐rolled AISI 304 austenitic stainless steels at travel speeds ranging from 40 to 100 mm/min with a constant rotating speed of 1000 rpm. Tensile strengths and hardness values of the weld interface were determined and microstructure features of these samples were investigated. 相似文献
8.
S. Grigoriev M. Volosova Y. Melnik N. Cherkasova 《Materialwissenschaft und Werkstofftechnik》2015,46(1):10-15
The article deals with the influence of the vacuum plasma surface treatment on the life of the face milling cutter of high‐speed steel R6M5 (analog M2 (USA, AISI/ASTM)). Such processing combines ion nitriding in gas plasma and the deposition of the wear‐resistant TiAlN layer in the metal gas plasma of the vacuum‐arc discharge. Research verifies that the use of vacuum plasma treatment combining the formation of the transition nitrided layer in the gas plasma and the subsequent deposition of TiAlN coating in metal gas plasma created by a vacuum‐arc discharge is an effective way to improve the tool life of high‐speed steel face milling cutters. 相似文献
9.
High‐boron high‐speed steel (HSS) is a cheap roll material. In the paper, the authors research the effect of heat treatment on the microstructure and properties of high‐boron high‐speed steel HSS roll containing 0.54% C, 1.96% B, 3.82% W, 7.06% Mo, 5.23% Cr and 2.62% Al by means of the optical microscopy (OM), the scanning electron microscopy (SEM), X‐ray diffraction (XRD) and hardness test. The results showed that as‐cast structure of boron‐bearing high‐speed steel HSS consisted of martensite, pearlite, M2(B, C), M3(B, C) and M23(B, C)6 type borocarbides. After quenching, the matrix transformed into the lath martensite, and M3(B, C) dissolved into the matrix. When quenching temperature is lower than 1050°C, the hardness is increased with the increase of quenching temperature under oil cooling, while quenching temperature excels 1100°C, the hardness will decrease with the increase of quenching temperature. Under the condition of salt bath and air cooling, the effect of quenching temperature on the hardness is similar to the above law, but the quenching temperature obtaining the highest hardness is higher than that of oil cooling. The highest hardness is obtained while tempering at 525°C. The hardness of high‐boron high‐speed steel HSS roll is 66.5 HRC, and its impact toughness excels 13.1 J/cm2. Using in pre‐finishing stands of high‐speed hot wire‐rod rolling mill, the wear rate of high‐boron HSS rolls is 0.26 mm/one thousand tons steel. However the manufacturing cost of high‐boron HSS rolls is obviously lower than that of powder metallurgy hard alloy rolls, it is only 28% of that of powder metallurgy (PM) hard alloy rolls. 相似文献
10.
T. Eckardt Dr.‐Ing. H. Manhardt D. F. Lupton 《Materialwissenschaft und Werkstofftechnik》2008,39(12):933-935
In order to enhance high‐temperature mechanical properties of platinum a dispersed particle hardening was developed by W. C. Heraeus, Hanau. A suitable compound impeding grain growth and migration of dislocations is zirconia. There are indications that significantly increased amounts of oxides might also stabilise erosion resistance of spark plug electrodes while reducing the percentage of cost‐intensive precious metal. Two different process technologies of manufacturing platinum/metal oxide composites are presented and compared: 1) melting and subsequent oxidation and 2) mixing of metal and oxide powders followed by extrusion. In both cases wires with typical diameters of 0.8 to 0.6 mm are fabricated. Samples with approx. 6 vol.‐% of zirconia dispersed in a platinum matrix were successfully tested under real life conditions in a combustion engine. 相似文献
11.
W. Bleck A. Frehn J. Ohlert H.‐M. Sonne G. Steinbeck 《Materialwissenschaft und Werkstofftechnik》2004,35(8):495-504
Influence of temperature and prestraining on the plastic material behaviour of modern sheet steels for autobody applications Within the scope of a common research project of the automotive and steel industry, characteristic values describing the plastical behaviour of 20 sheet steels have been determined. In detail, quasistatic tensile tests at the testing temperatures ‐40 °C, 23 °C and 100 °C were carried out to obtain flow curves for the as delivered materials as well as for steels after a defined prestraining or heat treatment. Additionally, sheet metal testing led to forming limit diagrams and limiting drawing ratios including the working ranges for deep drawing. The results of the tensile tests showed significant differences between steel groups with regard to their strain hardening behaviour, which can be described by the ratio of yield and tensile strength Rp0,2/Rm or the ΘIV‐value, and their temperature sensitivity. Within one steel group, consisting of steels with similar strain hardening behaviour, it might be possible to determine flow curves of one steel in a defined condition in order to calculate the flow curves of other steels with different strength. An advantage would be a lesser number of experimental tests which have to be performed in order to supply reliable input data for numerical material and component modelling. 相似文献
12.
D. N. Trushnikov V. Ya. Belenki'y G. M. Mladenov N. S. Portnov 《Materialwissenschaft und Werkstofftechnik》2012,43(10):892-897
The process of emission of term electrons from the zone of effect of the electron beam are analyzed. During the experiments, the samples of stainless steel and titanium alloy were welded. Experiments were conducted to examine the spectrum of oscillations of the secondary current at various values of the specific power of the electron beam. The conducted research showed that the signal spectrum of the secondary current in electron beam welding contains a characteristic high‐frequency (15…?25 kHz) component. It was established that the described frequency spectrum is not created by some control system in the electron beam machine and reflects the oscillations in the system – «keyhole‐plasma». Empirical density distribution of the high‐frequency signal was constructed in the amplitude range. It was shown that the parameters of the density distribution is closely linked with the nature of interaction between the beam with the metal and can be used for remote control of technology process. 相似文献
13.
M. Kaya M. Kılıç İ. Kırık E. M. Karakurt B. Gülenç 《Materialwissenschaft und Werkstofftechnik》2017,48(7):661-665
This work deals with diffusion bonded joints between Ti–6Al–4V alloy and interstitial free (IF) steel at different temperatures under a pressure of 5 MPa for 30 min. The effect of bonding temperature on the microstructure and mechanical properties of the joint interface was investigated using optic microscopy, a scanning electron microscope (SEM) equipped with X‐ray energy dispersive spectrometer (EDS) and shear strength measurements. The intermetallic phases such as FeTi and Fe2Ti occurred at the interface of bonded specimens. In addition, it was seen that shear strength of bonded specimens decreased with increasing temperature due to growing intermetallics. 相似文献
14.
Mechanical properties of high strength steel welded joints strictly depend on the welding process, the filler material composition and the welding geometry. This study investigates the effects of using cored and solid welding wires and implementing various groove angles on the mechanical performance of weld joints which were fabricated employing the gas metal arc welding process. It was found that weld joints of low alloy, high strength steels using low alloy steel cored welding wires exhibited higher tensile strength than that of low alloy steel solid wire and chromium‐nickel steel bare welding wire when the method of gas metal arc welding is employed. The effect of groove angle on the strength and toughness of V‐groove and double V‐groove butt‐joints was investigated. V‐groove joints, with higher tensile strength than double V‐groove joints in the whole range of groove angles, were superior in toughness for small groove angles, but impact toughness values of both joints were comparable for large angles. The effect of heat input and cooling rate on the weld microstructure and weld strength was also investigated by performing thermal analysis employing the commercial software ANSYS. It was concluded that cooling rate and solidification growth rate determined the microstructure of the weld zone which had great consequences in regard to mechanical properties. 相似文献
15.
A. V. Mikhaylovskaya A. D. Kotov V. S. Levchenko V. K. Portnoy 《Materialwissenschaft und Werkstofftechnik》2014,45(9):822-827
Al–Zn–Mg–Cu aluminum alloy contain 0.3% Zr and 4% Ni was processed by traditional hot and cold rolling with a total reduction from 0 to 80%. The relationship between superplastic behavior and reduction of cold deformation and casting cooling rate was analyzed. It is shown that the decrease in the reduction of cold rolling do not significantly influence on flow stress and elongation. Decrease in casting cooling rate leads to insignificantly decrease in superplastic indicators. Alloy exhibits advanced superplasticity: the elongation of 400–800% at the strain rates of (5 × 10–3–1 × 10–1) s–1. 相似文献
16.
Aiming at investigating the working of magneto‐rheological fluid absorber, a test system used for detecting the damping characteristics of the magneto‐rheological fluid absorber was designed. The test system included sensors, data acquisition card, and so on. The vibration signals were detected by the sensors, put into LabVIEW data acquisition system, and then collected through the processing of closed‐loop Proportion Integration Differentiation control algorithm. Considering that the feedback current could be output to the magneto‐rheological fluid absorber by the data acquisition card, thus the damping force could be changed. The test results showed that the amplitude of the structure vibration response was obviously reduced through the closed‐loop Proportion Integration Differentiation control algorithm, and the control damping characteristics of the magneto‐rheological fluid absorber was improved. 相似文献
17.
R. Hunter A. Vizán J. Peréz J. Möller J. Leyrer L.F.M. da Silva 《Materialwissenschaft und Werkstofftechnik》2017,48(6):546-555
This study proposes a novel method to strengthen fiber reinforced plastic (FRP) adherends in a single lap joint (SLJ) by using Kevlar threads. The adherend reinforcement procedure consists of applying a zigzag thread in the fiber glass layers that comprise the adherend in order to subsequently manufacture the adherends using the vacuum infusion method. For this study, three single lap joint configurations were used: Adherends without Kevlar reinforcement (SLJ1), adherends with Kevlar reinforcement with a medium step zigzag (SLJ2) and adherends with Kevlar reinforcement with a small step zigzag (SLJ3). Mechanical tensile tests were carried out to determine the ultimate strength and displacement of the single lap joint configurations studied. Adherends reinforced by Kevlar threads increase the strength and displacement of the single lap joint. However, the influence of the step size of zigzag threads on the adherend does not significantly influence the strength, but significantly affects the maximum displacement of the single lap joint. 相似文献
18.
S. Koch R. Büscher I. Tikhovski H. Brauer A. Runiewicz W. Dudzinski A. Fischer 《Materialwissenschaft und Werkstofftechnik》2002,33(12):705-715
Mechanische, chemische und tribologische Eigenschaften des Ni‐freien, hoch stickstoffhaltigen Stahls X13CrMnMoN18‐14‐3 (1.4452) Aufgrund der Probleme mit möglichen Ni‐Allergien besteht in der Medizintechnik die Forderung nach Ni‐freien Werkstoffen. Neben den bekannten Co‐ und Ti‐Basis Legierungen bieten die Ni‐freien hochstickstoffhaltigen Stähle eine kostengünstige Alternative. Der Stahl X13CrMnMoN18‐14‐3 (1.4452) ist ein Vertreter aus dieser Gruppe und wird in diesem Beitrag im lösungsgeglühten Zustand auf seine Korrosions‐, Ermüdungs‐ und Verschleißeigenschaften in Ringer Lösung untersucht und diskutiert. Im Vergleich zum üblichen medizinischen Edelstahl X2CrNiMo18‐15‐3 zeigt der 1.4452 unter allen Beanspruchungen bessere Eigenschaften. Das günstigere Ermüdungsverhalten wird durch die niedrige Stapelfehlerenergie bestimmt, während die besseren Korrosionseigenschaften auf den gelösten N zurückzuführen sind. Das sehr gute Gleitverschleißverhalten im artgleichen Kontakt wird durch das Zusammenwirken von beiden erreicht. Berücksichtigt man weiterhin das nicht‐zytotoxische Verhalten, kann man den Stahl 1.4452 als tauglich für medizinische Anwendungen bezeichnen. 相似文献
19.
M. A. Taha A. F. Yousef K. A. Gany H. A. Sabour 《Materialwissenschaft und Werkstofftechnik》2012,43(11):913-923
Selective laser melting is a laser‐based additive manufacturing process applying layer manufacturing technology and is used to produce dense parts from metallic powders. The application of selective laser melting on carbon steels is still limited due to difficulties arising from carbon content. This experimental investigation aims at gaining an understanding of the application of the process on ultra high carbon steel, which is a special alloy with remarkable structural properties suitable for different industrial applications. The feedstock ultra high carbon steel (2.1% C) powder, 20 μm to 106 μm was prepared by water atomizing technique. This powder was used for the selective laser melting to build specimens 10×10×40 mm in dimensions. To decrease the thermal stresses during layer by layer building, laser scanning was done through 5×5 mm random island patterns while layer thickness was 30 μm. Laser beam diameter, maximum power output, layer thickness and scan speed range were 0.2 mm, 100 W, 30 μm and 50–200 mm/s respectively. The process was done inside high purity nitrogen environment, with less than 0.5% oxygen content. The results illustrate the influence of scan speed from 50 to 200 mm/s on product geometry and dimensions, surface roughness, internal porosity and cracks, microstructure and surface hardness. The effect of post heat treatment by heating and holding for one hour (annealing) at different temperatures of 700°C, 750°C, 950°C is studied. The results indicate that selective laser melting is able to produce near to 95% density of ultra high carbon steel parts with acceptable geometry and surface quality. Porosity cracks, and microstructure formed during the process could be controlled through proper selection of process parameters and post heat treatment. Industrial ultra high carbon steel products can be rapidly fabricated by selective laser melting. 相似文献
20.
High speed milling experiments with cutting speeds of up to 7000 m/min have been performed on an aluminium alloy (AlZnMgCu1.5, AA 7075) and a steel (40CrMnMo7). Both materials were heat treated to produce a variety of microstructures in order to investigate the influence of microstructure on segmentation during chip formation. In case of the aluminium alloy it has been shown that chip formation is governed by the precipitation state, but not by the hardness of the material. In contrast, hardness can be used for a qualitative prediction of chip shape of the steel. In all cases, the chip formation mechanisms remain essentially unaffected by cutting speed, i.e. no transition from continuous to segmented chips occurred. 相似文献